Pull common extrinsics calibration code out into //frc971/vision
This sets us up to have a generic solver interface, and year specific
data munging.
Change-Id: I5cba597aa263d5061b7c71cd617706460ddb5f93
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/frc971/vision/BUILD b/frc971/vision/BUILD
index 1e3ed58..ca35f7c 100644
--- a/frc971/vision/BUILD
+++ b/frc971/vision/BUILD
@@ -33,3 +33,56 @@
"@com_google_absl//absl/base",
],
)
+
+cc_library(
+ name = "charuco_lib",
+ srcs = [
+ "charuco_lib.cc",
+ ],
+ hdrs = [
+ "charuco_lib.h",
+ ],
+ target_compatible_with = ["@platforms//os:linux"],
+ visibility = ["//visibility:public"],
+ deps = [
+ "//aos:flatbuffers",
+ "//aos/events:event_loop",
+ "//aos/network:message_bridge_server_fbs",
+ "//aos/network:team_number",
+ "//frc971/control_loops:quaternion_utils",
+ "//frc971/vision:vision_fbs",
+ "//third_party:opencv",
+ "//y2020/vision/sift:sift_fbs",
+ "//y2020/vision/sift:sift_training_fbs",
+ "//y2020/vision/tools/python_code:sift_training_data",
+ "@com_github_google_glog//:glog",
+ "@com_google_absl//absl/strings:str_format",
+ "@com_google_absl//absl/types:span",
+ "@org_tuxfamily_eigen//:eigen",
+ ],
+)
+
+cc_library(
+ name = "extrinsics_calibration",
+ srcs = [
+ "calibration_accumulator.cc",
+ "calibration_accumulator.h",
+ "extrinsics_calibration.cc",
+ "extrinsics_calibration.h",
+ ],
+ target_compatible_with = ["@platforms//os:linux"],
+ visibility = ["//visibility:public"],
+ deps = [
+ ":charuco_lib",
+ "//aos:init",
+ "//aos/events/logging:log_reader",
+ "//frc971/analysis:in_process_plotter",
+ "//frc971/control_loops/drivetrain:improved_down_estimator",
+ "//frc971/wpilib:imu_batch_fbs",
+ "//frc971/wpilib:imu_fbs",
+ "//third_party:opencv",
+ "@com_google_absl//absl/strings:str_format",
+ "@com_google_ceres_solver//:ceres",
+ "@org_tuxfamily_eigen//:eigen",
+ ],
+)
diff --git a/frc971/vision/calibration_accumulator.cc b/frc971/vision/calibration_accumulator.cc
new file mode 100644
index 0000000..89945b0
--- /dev/null
+++ b/frc971/vision/calibration_accumulator.cc
@@ -0,0 +1,172 @@
+#include "frc971/vision/calibration_accumulator.h"
+
+#include <opencv2/aruco/charuco.hpp>
+#include <opencv2/calib3d.hpp>
+#include <opencv2/features2d.hpp>
+#include <opencv2/highgui/highgui.hpp>
+#include <opencv2/imgproc.hpp>
+
+#include "Eigen/Dense"
+#include "aos/events/simulated_event_loop.h"
+#include "aos/time/time.h"
+#include "frc971/control_loops/quaternion_utils.h"
+#include "frc971/wpilib/imu_batch_generated.h"
+#include "frc971/vision/charuco_lib.h"
+
+DEFINE_bool(display_undistorted, false,
+ "If true, display the undistorted image.");
+
+namespace frc971 {
+namespace vision {
+using aos::distributed_clock;
+using aos::monotonic_clock;
+namespace chrono = std::chrono;
+
+constexpr double kG = 9.807;
+
+void CalibrationData::AddCameraPose(
+ distributed_clock::time_point distributed_now, Eigen::Vector3d rvec,
+ Eigen::Vector3d tvec) {
+ // Always start with IMU reading...
+ if (!imu_points_.empty() && imu_points_[0].first < distributed_now) {
+ rot_trans_points_.emplace_back(distributed_now, std::make_pair(rvec, tvec));
+ }
+}
+
+void CalibrationData::AddImu(distributed_clock::time_point distributed_now,
+ Eigen::Vector3d gyro, Eigen::Vector3d accel) {
+ imu_points_.emplace_back(distributed_now, std::make_pair(gyro, accel));
+}
+
+void CalibrationData::ReviewData(CalibrationDataObserver *observer) const {
+ size_t next_imu_point = 0;
+ size_t next_camera_point = 0;
+ while (true) {
+ if (next_imu_point != imu_points_.size()) {
+ // There aren't that many combinations, so just brute force them all
+ // rather than being too clever.
+ if (next_camera_point != rot_trans_points_.size()) {
+ if (imu_points_[next_imu_point].first >
+ rot_trans_points_[next_camera_point].first) {
+ // Camera!
+ observer->UpdateCamera(rot_trans_points_[next_camera_point].first,
+ rot_trans_points_[next_camera_point].second);
+ ++next_camera_point;
+ } else {
+ // IMU!
+ observer->UpdateIMU(imu_points_[next_imu_point].first,
+ imu_points_[next_imu_point].second);
+ ++next_imu_point;
+ }
+ } else {
+ if (next_camera_point != rot_trans_points_.size()) {
+ // Camera!
+ observer->UpdateCamera(rot_trans_points_[next_camera_point].first,
+ rot_trans_points_[next_camera_point].second);
+ ++next_camera_point;
+ } else {
+ // Nothing left for either list of points, so we are done.
+ break;
+ }
+ }
+ }
+ }
+}
+
+Calibration::Calibration(aos::SimulatedEventLoopFactory *event_loop_factory,
+ aos::EventLoop *image_event_loop,
+ aos::EventLoop *imu_event_loop, std::string_view pi,
+ CalibrationData *data)
+ : image_event_loop_(image_event_loop),
+ image_factory_(event_loop_factory->GetNodeEventLoopFactory(
+ image_event_loop_->node())),
+ imu_event_loop_(imu_event_loop),
+ imu_factory_(
+ event_loop_factory->GetNodeEventLoopFactory(imu_event_loop_->node())),
+ charuco_extractor_(
+ image_event_loop_, pi,
+ [this](cv::Mat rgb_image, monotonic_clock::time_point eof,
+ std::vector<int> charuco_ids,
+ std::vector<cv::Point2f> charuco_corners, bool valid,
+ Eigen::Vector3d rvec_eigen, Eigen::Vector3d tvec_eigen) {
+ HandleCharuco(rgb_image, eof, charuco_ids, charuco_corners, valid,
+ rvec_eigen, tvec_eigen);
+ }),
+ data_(data) {
+ imu_factory_->OnShutdown([]() { cv::destroyAllWindows(); });
+
+ imu_event_loop_->MakeWatcher(
+ "/drivetrain", [this](const frc971::IMUValuesBatch &imu) {
+ if (!imu.has_readings()) {
+ return;
+ }
+ for (const frc971::IMUValues *value : *imu.readings()) {
+ HandleIMU(value);
+ }
+ });
+}
+
+void Calibration::HandleCharuco(cv::Mat rgb_image,
+ const monotonic_clock::time_point eof,
+ std::vector<int> /*charuco_ids*/,
+ std::vector<cv::Point2f> /*charuco_corners*/,
+ bool valid, Eigen::Vector3d rvec_eigen,
+ Eigen::Vector3d tvec_eigen) {
+ if (valid) {
+ data_->AddCameraPose(image_factory_->ToDistributedClock(eof), rvec_eigen,
+ tvec_eigen);
+
+ // Z -> up
+ // Y -> away from cameras 2 and 3
+ // X -> left
+ Eigen::Vector3d imu(last_value_.accelerometer_x,
+ last_value_.accelerometer_y,
+ last_value_.accelerometer_z);
+
+ Eigen::Quaternion<double> imu_to_camera(
+ Eigen::AngleAxisd(-0.5 * M_PI, Eigen::Vector3d::UnitX()));
+
+ Eigen::Quaternion<double> board_to_world(
+ Eigen::AngleAxisd(0.5 * M_PI, Eigen::Vector3d::UnitX()));
+
+ Eigen::IOFormat HeavyFmt(Eigen::FullPrecision, 0, ", ", ",\n", "[", "]",
+ "[", "]");
+
+ const double age_double =
+ std::chrono::duration_cast<std::chrono::duration<double>>(
+ image_event_loop_->monotonic_now() - eof)
+ .count();
+ LOG(INFO) << std::fixed << std::setprecision(6) << "Age: " << age_double
+ << ", Pose is R:" << rvec_eigen.transpose().format(HeavyFmt)
+ << " T:" << tvec_eigen.transpose().format(HeavyFmt);
+ }
+
+ cv::imshow("Display", rgb_image);
+
+ if (FLAGS_display_undistorted) {
+ const cv::Size image_size(rgb_image.cols, rgb_image.rows);
+ cv::Mat undistorted_rgb_image(image_size, CV_8UC3);
+ cv::undistort(rgb_image, undistorted_rgb_image,
+ charuco_extractor_.camera_matrix(),
+ charuco_extractor_.dist_coeffs());
+
+ cv::imshow("Display undist", undistorted_rgb_image);
+ }
+}
+
+void Calibration::HandleIMU(const frc971::IMUValues *imu) {
+ VLOG(1) << "IMU " << imu;
+ imu->UnPackTo(&last_value_);
+ Eigen::Vector3d gyro(last_value_.gyro_x, last_value_.gyro_y,
+ last_value_.gyro_z);
+ Eigen::Vector3d accel(last_value_.accelerometer_x,
+ last_value_.accelerometer_y,
+ last_value_.accelerometer_z);
+
+ data_->AddImu(imu_factory_->ToDistributedClock(monotonic_clock::time_point(
+ chrono::nanoseconds(imu->monotonic_timestamp_ns()))),
+ gyro, accel * kG);
+}
+
+} // namespace vision
+} // namespace frc971
diff --git a/frc971/vision/calibration_accumulator.h b/frc971/vision/calibration_accumulator.h
new file mode 100644
index 0000000..6d42708
--- /dev/null
+++ b/frc971/vision/calibration_accumulator.h
@@ -0,0 +1,95 @@
+#ifndef Y2020_VISION_CALIBRATION_ACCUMULATOR_H_
+#define Y2020_VISION_CALIBRATION_ACCUMULATOR_H_
+
+#include <vector>
+
+#include "Eigen/Dense"
+#include "aos/events/simulated_event_loop.h"
+#include "aos/time/time.h"
+#include "frc971/control_loops/quaternion_utils.h"
+#include "frc971/vision/charuco_lib.h"
+#include "frc971/wpilib/imu_batch_generated.h"
+
+namespace frc971 {
+namespace vision {
+
+// This class provides an interface for an application to be notified of all
+// camera and IMU samples in order with the correct timestamps.
+class CalibrationDataObserver {
+ public:
+ // Observes a camera sample at the corresponding time t, and with the
+ // corresponding rotation and translation vectors rt.
+ virtual void UpdateCamera(aos::distributed_clock::time_point t,
+ std::pair<Eigen::Vector3d, Eigen::Vector3d> rt) = 0;
+
+ // Observes an IMU sample at the corresponding time t, and with the
+ // corresponding angular velocity and linear acceleration vectors wa.
+ virtual void UpdateIMU(aos::distributed_clock::time_point t,
+ std::pair<Eigen::Vector3d, Eigen::Vector3d> wa) = 0;
+};
+
+// Class to both accumulate and replay camera and IMU data in time order.
+class CalibrationData {
+ public:
+ // Adds a camera/charuco detection to the list at the provided time.
+ // This has only been tested with a charuco board.
+ void AddCameraPose(aos::distributed_clock::time_point distributed_now,
+ Eigen::Vector3d rvec, Eigen::Vector3d tvec);
+
+ // Adds an IMU point to the list at the provided time.
+ void AddImu(aos::distributed_clock::time_point distributed_now,
+ Eigen::Vector3d gyro, Eigen::Vector3d accel);
+
+ // Processes the data points by calling UpdateCamera and UpdateIMU in time
+ // order.
+ void ReviewData(CalibrationDataObserver *observer) const;
+
+ size_t camera_samples_size() const { return rot_trans_points_.size(); }
+
+ private:
+ std::vector<std::pair<aos::distributed_clock::time_point,
+ std::pair<Eigen::Vector3d, Eigen::Vector3d>>>
+ imu_points_;
+
+ // Store pose samples as timestamp, along with
+ // pair of rotation, translation vectors
+ std::vector<std::pair<aos::distributed_clock::time_point,
+ std::pair<Eigen::Vector3d, Eigen::Vector3d>>>
+ rot_trans_points_;
+};
+
+// Class to register image and IMU callbacks in AOS and route them to the
+// corresponding CalibrationData class.
+class Calibration {
+ public:
+ Calibration(aos::SimulatedEventLoopFactory *event_loop_factory,
+ aos::EventLoop *image_event_loop, aos::EventLoop *imu_event_loop,
+ std::string_view pi, CalibrationData *data);
+
+ // Processes a charuco detection.
+ void HandleCharuco(cv::Mat rgb_image,
+ const aos::monotonic_clock::time_point eof,
+ std::vector<int> /*charuco_ids*/,
+ std::vector<cv::Point2f> /*charuco_corners*/, bool valid,
+ Eigen::Vector3d rvec_eigen, Eigen::Vector3d tvec_eigen);
+
+ // Processes an IMU reading.
+ void HandleIMU(const frc971::IMUValues *imu);
+
+ private:
+ aos::EventLoop *image_event_loop_;
+ aos::NodeEventLoopFactory *image_factory_;
+ aos::EventLoop *imu_event_loop_;
+ aos::NodeEventLoopFactory *imu_factory_;
+
+ CharucoExtractor charuco_extractor_;
+
+ CalibrationData *data_;
+
+ frc971::IMUValuesT last_value_;
+};
+
+} // namespace vision
+} // namespace frc971
+
+#endif // Y2020_VISION_CALIBRATION_ACCUMULATOR_H_
diff --git a/frc971/vision/charuco_lib.cc b/frc971/vision/charuco_lib.cc
new file mode 100644
index 0000000..f14c9fd
--- /dev/null
+++ b/frc971/vision/charuco_lib.cc
@@ -0,0 +1,289 @@
+#include "frc971/vision/charuco_lib.h"
+
+#include <chrono>
+#include <functional>
+#include <opencv2/core/eigen.hpp>
+#include <opencv2/highgui/highgui.hpp>
+#include <opencv2/imgproc.hpp>
+#include <string_view>
+
+#include "aos/events/event_loop.h"
+#include "aos/flatbuffers.h"
+#include "aos/network/team_number.h"
+#include "frc971/control_loops/quaternion_utils.h"
+#include "frc971/vision/vision_generated.h"
+#include "glog/logging.h"
+#include "y2020/vision/sift/sift_generated.h"
+#include "y2020/vision/sift/sift_training_generated.h"
+#include "y2020/vision/tools/python_code/sift_training_data.h"
+
+DEFINE_uint32(min_targets, 10,
+ "The mininum number of targets required to match.");
+DEFINE_bool(large_board, true, "If true, use the large calibration board.");
+DEFINE_bool(coarse_pattern, true, "If true, use coarse arucos; else, use fine");
+DEFINE_string(board_template_path, "",
+ "If specified, write an image to the specified path for the "
+ "charuco board pattern.");
+
+namespace frc971 {
+namespace vision {
+namespace chrono = std::chrono;
+using aos::monotonic_clock;
+
+CameraCalibration::CameraCalibration(
+ const absl::Span<const uint8_t> training_data_bfbs, std::string_view pi) {
+ const aos::FlatbufferSpan<sift::TrainingData> training_data(
+ training_data_bfbs);
+ CHECK(training_data.Verify());
+ camera_calibration_ = FindCameraCalibration(&training_data.message(), pi);
+}
+
+cv::Mat CameraCalibration::CameraIntrinsics() const {
+ const cv::Mat result(3, 3, CV_32F,
+ const_cast<void *>(static_cast<const void *>(
+ camera_calibration_->intrinsics()->data())));
+ CHECK_EQ(result.total(), camera_calibration_->intrinsics()->size());
+ return result;
+}
+
+Eigen::Matrix3d CameraCalibration::CameraIntrinsicsEigen() const {
+ cv::Mat camera_intrinsics = CameraIntrinsics();
+ Eigen::Matrix3d result;
+ cv::cv2eigen(camera_intrinsics, result);
+ return result;
+}
+
+cv::Mat CameraCalibration::CameraDistCoeffs() const {
+ const cv::Mat result(5, 1, CV_32F,
+ const_cast<void *>(static_cast<const void *>(
+ camera_calibration_->dist_coeffs()->data())));
+ CHECK_EQ(result.total(), camera_calibration_->dist_coeffs()->size());
+ return result;
+}
+
+const sift::CameraCalibration *CameraCalibration::FindCameraCalibration(
+ const sift::TrainingData *const training_data, std::string_view pi) const {
+ std::optional<uint16_t> pi_number = aos::network::ParsePiNumber(pi);
+ std::optional<uint16_t> team_number =
+ aos::network::team_number_internal::ParsePiTeamNumber(pi);
+ CHECK(pi_number);
+ CHECK(team_number);
+ const std::string node_name = absl::StrFormat("pi%d", pi_number.value());
+ LOG(INFO) << "Looking for node name " << node_name << " team number "
+ << team_number.value();
+ for (const sift::CameraCalibration *candidate :
+ *training_data->camera_calibrations()) {
+ if (candidate->node_name()->string_view() != node_name) {
+ continue;
+ }
+ if (candidate->team_number() != team_number.value()) {
+ continue;
+ }
+ return candidate;
+ }
+ LOG(FATAL) << ": Failed to find camera calibration for " << node_name
+ << " on " << team_number.value();
+}
+
+ImageCallback::ImageCallback(
+ aos::EventLoop *event_loop, std::string_view channel,
+ std::function<void(cv::Mat, monotonic_clock::time_point)> &&fn)
+ : event_loop_(event_loop),
+ server_fetcher_(
+ event_loop_->MakeFetcher<aos::message_bridge::ServerStatistics>(
+ "/aos")),
+ source_node_(aos::configuration::GetNode(
+ event_loop_->configuration(),
+ event_loop_->GetChannel<CameraImage>(channel)
+ ->source_node()
+ ->string_view())),
+ handle_image_(std::move(fn)) {
+ event_loop_->MakeWatcher(channel, [this](const CameraImage &image) {
+ const monotonic_clock::time_point eof_source_node =
+ monotonic_clock::time_point(
+ chrono::nanoseconds(image.monotonic_timestamp_ns()));
+ chrono::nanoseconds offset{0};
+ if (source_node_ != event_loop_->node()) {
+ server_fetcher_.Fetch();
+ if (!server_fetcher_.get()) {
+ return;
+ }
+
+ // If we are viewing this image from another node, convert to our
+ // monotonic clock.
+ const aos::message_bridge::ServerConnection *server_connection = nullptr;
+
+ for (const aos::message_bridge::ServerConnection *connection :
+ *server_fetcher_->connections()) {
+ CHECK(connection->has_node());
+ if (connection->node()->name()->string_view() ==
+ source_node_->name()->string_view()) {
+ server_connection = connection;
+ break;
+ }
+ }
+
+ CHECK(server_connection != nullptr) << ": Failed to find client";
+ if (!server_connection->has_monotonic_offset()) {
+ VLOG(1) << "No offset yet.";
+ return;
+ }
+ offset = chrono::nanoseconds(server_connection->monotonic_offset());
+ }
+
+ const monotonic_clock::time_point eof = eof_source_node - offset;
+
+ const monotonic_clock::duration age = event_loop_->monotonic_now() - eof;
+ const double age_double =
+ std::chrono::duration_cast<std::chrono::duration<double>>(age).count();
+ if (age > std::chrono::milliseconds(100)) {
+ VLOG(2) << "Age: " << age_double << ", getting behind, skipping";
+ return;
+ }
+ // Create color image:
+ cv::Mat image_color_mat(cv::Size(image.cols(), image.rows()), CV_8UC2,
+ (void *)image.data()->data());
+ const cv::Size image_size(image.cols(), image.rows());
+ cv::Mat rgb_image(image_size, CV_8UC3);
+ cv::cvtColor(image_color_mat, rgb_image, cv::COLOR_YUV2BGR_YUYV);
+ handle_image_(rgb_image, eof);
+ });
+}
+
+CharucoExtractor::CharucoExtractor(
+ aos::EventLoop *event_loop, std::string_view pi,
+ std::function<void(cv::Mat, monotonic_clock::time_point, std::vector<int>,
+ std::vector<cv::Point2f>, bool, Eigen::Vector3d,
+ Eigen::Vector3d)> &&fn)
+ : event_loop_(event_loop),
+ calibration_(SiftTrainingData(), pi),
+ dictionary_(cv::aruco::getPredefinedDictionary(
+ FLAGS_large_board ? cv::aruco::DICT_5X5_250
+ : cv::aruco::DICT_6X6_250)),
+ board_(
+ FLAGS_large_board
+ ? (FLAGS_coarse_pattern ? cv::aruco::CharucoBoard::create(
+ 12, 9, 0.06, 0.04666, dictionary_)
+ : cv::aruco::CharucoBoard::create(
+ 25, 18, 0.03, 0.0233, dictionary_))
+ : (FLAGS_coarse_pattern ? cv::aruco::CharucoBoard::create(
+ 7, 5, 0.04, 0.025, dictionary_)
+ // TODO(jim): Need to figure out what size
+ // is for small board, fine pattern
+ : cv::aruco::CharucoBoard::create(
+ 7, 5, 0.03, 0.0233, dictionary_))),
+ camera_matrix_(calibration_.CameraIntrinsics()),
+ eigen_camera_matrix_(calibration_.CameraIntrinsicsEigen()),
+ dist_coeffs_(calibration_.CameraDistCoeffs()),
+ pi_number_(aos::network::ParsePiNumber(pi)),
+ image_callback_(
+ event_loop,
+ absl::StrCat("/pi", std::to_string(pi_number_.value()), "/camera"),
+ [this](cv::Mat rgb_image, const monotonic_clock::time_point eof) {
+ HandleImage(rgb_image, eof);
+ }),
+ handle_charuco_(std::move(fn)) {
+ LOG(INFO) << "Using " << (FLAGS_large_board ? "large" : "small")
+ << " board with " << (FLAGS_coarse_pattern ? "coarse" : "fine")
+ << " pattern";
+ if (!FLAGS_board_template_path.empty()) {
+ cv::Mat board_image;
+ board_->draw(cv::Size(600, 500), board_image, 10, 1);
+ cv::imwrite(FLAGS_board_template_path, board_image);
+ }
+
+ LOG(INFO) << "Camera matrix " << camera_matrix_;
+ LOG(INFO) << "Distortion Coefficients " << dist_coeffs_;
+
+ CHECK(pi_number_) << ": Invalid pi number " << pi
+ << ", failed to parse pi number";
+
+ LOG(INFO) << "Connecting to channel /pi" << pi_number_.value() << "/camera";
+}
+
+void CharucoExtractor::HandleImage(cv::Mat rgb_image,
+ const monotonic_clock::time_point eof) {
+ const double age_double =
+ std::chrono::duration_cast<std::chrono::duration<double>>(
+ event_loop_->monotonic_now() - eof)
+ .count();
+ std::vector<int> marker_ids;
+ std::vector<std::vector<cv::Point2f>> marker_corners;
+
+ cv::aruco::detectMarkers(rgb_image, board_->dictionary, marker_corners,
+ marker_ids);
+
+ std::vector<cv::Point2f> charuco_corners;
+ std::vector<int> charuco_ids;
+ bool valid = false;
+ Eigen::Vector3d rvec_eigen = Eigen::Vector3d::Zero();
+ Eigen::Vector3d tvec_eigen = Eigen::Vector3d::Zero();
+
+ // If at least one marker detected
+ if (marker_ids.size() >= FLAGS_min_targets) {
+ // Run everything twice, once with the calibration, and once
+ // without. This lets us both calibrate, and also print out the pose
+ // real time with the previous calibration.
+ cv::aruco::interpolateCornersCharuco(marker_corners, marker_ids, rgb_image,
+ board_, charuco_corners, charuco_ids);
+
+ std::vector<cv::Point2f> charuco_corners_with_calibration;
+ std::vector<int> charuco_ids_with_calibration;
+
+ cv::aruco::interpolateCornersCharuco(
+ marker_corners, marker_ids, rgb_image, board_,
+ charuco_corners_with_calibration, charuco_ids_with_calibration,
+ camera_matrix_, dist_coeffs_);
+
+ cv::aruco::drawDetectedMarkers(rgb_image, marker_corners, marker_ids);
+
+ if (charuco_ids.size() >= FLAGS_min_targets) {
+ cv::aruco::drawDetectedCornersCharuco(rgb_image, charuco_corners,
+ charuco_ids, cv::Scalar(255, 0, 0));
+
+ cv::Vec3d rvec, tvec;
+ valid = cv::aruco::estimatePoseCharucoBoard(
+ charuco_corners_with_calibration, charuco_ids_with_calibration,
+ board_, camera_matrix_, dist_coeffs_, rvec, tvec);
+
+ // if charuco pose is valid
+ if (valid) {
+ cv::cv2eigen(rvec, rvec_eigen);
+ cv::cv2eigen(tvec, tvec_eigen);
+
+ Eigen::Quaternion<double> rotation(
+ frc971::controls::ToQuaternionFromRotationVector(rvec_eigen));
+ Eigen::Translation3d translation(tvec_eigen);
+
+ const Eigen::Affine3d board_to_camera = translation * rotation;
+
+ Eigen::Matrix<double, 3, 4> camera_projection =
+ Eigen::Matrix<double, 3, 4>::Identity();
+ Eigen::Vector3d result = eigen_camera_matrix_ * camera_projection *
+ board_to_camera * Eigen::Vector3d::Zero();
+
+ result /= result.z();
+ cv::circle(rgb_image, cv::Point(result.x(), result.y()), 4,
+ cv::Scalar(255, 255, 255), 0, cv::LINE_8);
+
+ cv::aruco::drawAxis(rgb_image, camera_matrix_, dist_coeffs_, rvec, tvec,
+ 0.1);
+ } else {
+ LOG(INFO) << "Age: " << age_double << ", invalid pose";
+ }
+ } else {
+ LOG(INFO) << "Age: " << age_double << ", not enough charuco IDs, got "
+ << charuco_ids.size() << ", needed " << FLAGS_min_targets;
+ }
+ } else {
+ LOG(INFO) << "Age: " << age_double << ", not enough marker IDs, got "
+ << marker_ids.size() << ", needed " << FLAGS_min_targets;
+ cv::aruco::drawDetectedMarkers(rgb_image, marker_corners, marker_ids);
+ }
+
+ handle_charuco_(rgb_image, eof, charuco_ids, charuco_corners, valid,
+ rvec_eigen, tvec_eigen);
+}
+
+} // namespace vision
+} // namespace frc971
diff --git a/frc971/vision/charuco_lib.h b/frc971/vision/charuco_lib.h
new file mode 100644
index 0000000..a54bfca
--- /dev/null
+++ b/frc971/vision/charuco_lib.h
@@ -0,0 +1,117 @@
+#ifndef Y2020_VISION_CHARUCO_LIB_H_
+#define Y2020_VISION_CHARUCO_LIB_H_
+
+#include <functional>
+#include <string_view>
+
+#include <opencv2/aruco/charuco.hpp>
+#include <opencv2/calib3d.hpp>
+#include "Eigen/Dense"
+#include "Eigen/Geometry"
+
+#include "absl/types/span.h"
+#include "aos/events/event_loop.h"
+#include "aos/network/message_bridge_server_generated.h"
+#include "y2020/vision/sift/sift_generated.h"
+#include "y2020/vision/sift/sift_training_generated.h"
+
+namespace frc971 {
+namespace vision {
+
+// Class to find extrinsics for a specified pi's camera using the provided
+// training data.
+class CameraCalibration {
+ public:
+ CameraCalibration(const absl::Span<const uint8_t> training_data_bfbs,
+ std::string_view pi);
+
+ // Intrinsics for the located camera.
+ cv::Mat CameraIntrinsics() const;
+ Eigen::Matrix3d CameraIntrinsicsEigen() const;
+
+ // Distortion coefficients for the located camera.
+ cv::Mat CameraDistCoeffs() const;
+
+ private:
+ // Finds the camera specific calibration flatbuffer.
+ const sift::CameraCalibration *FindCameraCalibration(
+ const sift::TrainingData *const training_data, std::string_view pi) const;
+
+ // Pointer to this camera's calibration parameters.
+ const sift::CameraCalibration *camera_calibration_;
+};
+
+// Class to call a function with a cv::Mat and age when an image shows up on the
+// provided channel. This hides all the conversions and wrangling needed to
+// view the image.
+class ImageCallback {
+ public:
+ ImageCallback(
+ aos::EventLoop *event_loop, std::string_view channel,
+ std::function<void(cv::Mat, aos::monotonic_clock::time_point)> &&fn);
+
+ private:
+ aos::EventLoop *event_loop_;
+ aos::Fetcher<aos::message_bridge::ServerStatistics> server_fetcher_;
+ const aos::Node *source_node_;
+ std::function<void(cv::Mat, aos::monotonic_clock::time_point)> handle_image_;
+};
+
+// Class which calls a callback each time an image arrives with the information
+// extracted from it.
+class CharucoExtractor {
+ public:
+ // The callback takes the following arguments:
+ // cv::Mat -> image with overlays drawn on it.
+ // monotonic_clock::time_point -> Time on this node when this image was
+ // captured.
+ // std::vector<int> -> charuco_ids
+ // std::vector<cv::Point2f> -> charuco_corners
+ // bool -> true if rvec/tvec is valid.
+ // Eigen::Vector3d -> rvec
+ // Eigen::Vector3d -> tvec
+ CharucoExtractor(
+ aos::EventLoop *event_loop, std::string_view pi,
+ std::function<void(cv::Mat, aos::monotonic_clock::time_point,
+ std::vector<int>, std::vector<cv::Point2f>, bool,
+ Eigen::Vector3d, Eigen::Vector3d)> &&fn);
+
+ // Returns the aruco dictionary in use.
+ cv::Ptr<cv::aruco::Dictionary> dictionary() const { return dictionary_; }
+ // Returns the aruco board in use.
+ cv::Ptr<cv::aruco::CharucoBoard> board() const { return board_; }
+
+ // Returns the camera matrix for this camera.
+ const cv::Mat camera_matrix() const { return camera_matrix_; }
+ // Returns the distortion coefficients for this camera.
+ const cv::Mat dist_coeffs() const { return dist_coeffs_; }
+
+ private:
+ // Handles the image by detecting the charuco board in it.
+ void HandleImage(cv::Mat rgb_image, aos::monotonic_clock::time_point eof);
+
+ aos::EventLoop *event_loop_;
+ CameraCalibration calibration_;
+
+ cv::Ptr<cv::aruco::Dictionary> dictionary_;
+ cv::Ptr<cv::aruco::CharucoBoard> board_;
+
+ const cv::Mat camera_matrix_;
+ const Eigen::Matrix3d eigen_camera_matrix_;
+ const cv::Mat dist_coeffs_;
+
+ const std::optional<uint16_t> pi_number_;
+
+ ImageCallback image_callback_;
+
+ // Function to call.
+ std::function<void(cv::Mat, aos::monotonic_clock::time_point,
+ std::vector<int>, std::vector<cv::Point2f>, bool,
+ Eigen::Vector3d, Eigen::Vector3d)>
+ handle_charuco_;
+};
+
+} // namespace vision
+} // namespace frc971
+
+#endif // Y2020_VISION_CHARUCO_LIB_H_
diff --git a/frc971/vision/extrinsics_calibration.cc b/frc971/vision/extrinsics_calibration.cc
new file mode 100644
index 0000000..627769b
--- /dev/null
+++ b/frc971/vision/extrinsics_calibration.cc
@@ -0,0 +1,634 @@
+#include "frc971/vision/extrinsics_calibration.h"
+
+#include "aos/time/time.h"
+#include "ceres/ceres.h"
+#include "frc971/analysis/in_process_plotter.h"
+#include "frc971/control_loops/runge_kutta.h"
+#include "frc971/vision/calibration_accumulator.h"
+#include "frc971/vision/charuco_lib.h"
+
+namespace frc971 {
+namespace vision {
+
+namespace chrono = std::chrono;
+using aos::distributed_clock;
+using aos::monotonic_clock;
+
+constexpr double kGravity = 9.8;
+
+// The basic ideas here are taken from Kalibr.
+// (https://github.com/ethz-asl/kalibr), but adapted to work with AOS, and to be
+// simpler.
+//
+// Camera readings and IMU readings come in at different times, on different
+// time scales. Our first problem is to align them in time so we can actually
+// compute an error. This is done in the calibration accumulator code. The
+// kalibr paper uses splines, while this uses kalman filters to solve the same
+// interpolation problem so we can get the expected vs actual pose at the time
+// each image arrives.
+//
+// The cost function is then fed the computed angular and positional error for
+// each camera sample before the kalman filter update. Intuitively, the smaller
+// the corrections to the kalman filter each step, the better the estimate
+// should be.
+//
+// We don't actually implement the angular kalman filter because the IMU is so
+// good. We give the solver an initial position and bias, and let it solve from
+// there. This lets us represent drift that is linear in time, which should be
+// good enough for ~1 minute calibration.
+//
+// TODO(austin): Kalman smoother ala
+// https://stanford.edu/~boyd/papers/pdf/auto_ks.pdf should allow for better
+// parallelism, and since we aren't causal, will take that into account a lot
+// better.
+
+// This class takes the initial parameters and biases, and computes the error
+// between the measured and expected camera readings. When optimized, this
+// gives us a cost function to minimize.
+template <typename Scalar>
+class CeresPoseFilter : public CalibrationDataObserver {
+ public:
+ typedef Eigen::Transform<Scalar, 3, Eigen::Affine> Affine3s;
+
+ CeresPoseFilter(Eigen::Quaternion<Scalar> initial_orientation,
+ Eigen::Quaternion<Scalar> imu_to_camera,
+ Eigen::Matrix<Scalar, 3, 1> gyro_bias,
+ Eigen::Matrix<Scalar, 6, 1> initial_state,
+ Eigen::Quaternion<Scalar> board_to_world,
+ Eigen::Matrix<Scalar, 3, 1> imu_to_camera_translation,
+ Scalar gravity_scalar,
+ Eigen::Matrix<Scalar, 3, 1> accelerometer_bias)
+ : accel_(Eigen::Matrix<double, 3, 1>::Zero()),
+ omega_(Eigen::Matrix<double, 3, 1>::Zero()),
+ imu_bias_(gyro_bias),
+ orientation_(initial_orientation),
+ x_hat_(initial_state),
+ p_(Eigen::Matrix<Scalar, 6, 6>::Zero()),
+ imu_to_camera_rotation_(imu_to_camera),
+ imu_to_camera_translation_(imu_to_camera_translation),
+ board_to_world_(board_to_world),
+ gravity_scalar_(gravity_scalar),
+ accelerometer_bias_(accelerometer_bias) {}
+
+ Scalar gravity_scalar() { return gravity_scalar_; }
+
+ virtual void ObserveCameraUpdate(
+ distributed_clock::time_point /*t*/,
+ Eigen::Vector3d /*board_to_camera_rotation*/,
+ Eigen::Quaternion<Scalar> /*imu_to_world_rotation*/,
+ Affine3s /*imu_to_world*/) {}
+
+ // Observes a camera measurement by applying a kalman filter correction and
+ // accumulating up the error associated with the step.
+ void UpdateCamera(distributed_clock::time_point t,
+ std::pair<Eigen::Vector3d, Eigen::Vector3d> rt) override {
+ Integrate(t);
+
+ const Eigen::Quaternion<Scalar> board_to_camera_rotation(
+ frc971::controls::ToQuaternionFromRotationVector(rt.first)
+ .cast<Scalar>());
+ const Affine3s board_to_camera =
+ Eigen::Translation3d(rt.second).cast<Scalar>() *
+ board_to_camera_rotation;
+
+ const Affine3s imu_to_camera =
+ imu_to_camera_translation_ * imu_to_camera_rotation_;
+
+ // This converts us from (facing the board),
+ // x right, y up, z towards us -> x right, y away, z up.
+ // Confirmed to be right.
+
+ // Want world -> imu rotation.
+ // world <- board <- camera <- imu.
+ const Eigen::Quaternion<Scalar> imu_to_world_rotation =
+ board_to_world_ * board_to_camera_rotation.inverse() *
+ imu_to_camera_rotation_;
+
+ const Affine3s imu_to_world =
+ board_to_world_ * board_to_camera.inverse() * imu_to_camera;
+
+ const Eigen::Matrix<Scalar, 3, 1> z =
+ imu_to_world * Eigen::Matrix<Scalar, 3, 1>::Zero();
+
+ Eigen::Matrix<Scalar, 3, 6> H = Eigen::Matrix<Scalar, 3, 6>::Zero();
+ H(0, 0) = static_cast<Scalar>(1.0);
+ H(1, 1) = static_cast<Scalar>(1.0);
+ H(2, 2) = static_cast<Scalar>(1.0);
+ const Eigen::Matrix<Scalar, 3, 1> y = z - H * x_hat_;
+
+ const Eigen::Matrix<double, 3, 3> R =
+ (::Eigen::DiagonalMatrix<double, 3>().diagonal() << ::std::pow(0.01, 2),
+ ::std::pow(0.01, 2), ::std::pow(0.01, 2))
+ .finished()
+ .asDiagonal();
+
+ const Eigen::Matrix<Scalar, 3, 3> S =
+ H * p_ * H.transpose() + R.cast<Scalar>();
+ const Eigen::Matrix<Scalar, 6, 3> K = p_ * H.transpose() * S.inverse();
+
+ x_hat_ += K * y;
+ p_ = (Eigen::Matrix<Scalar, 6, 6>::Identity() - K * H) * p_;
+
+ const Eigen::Quaternion<Scalar> error(imu_to_world_rotation.inverse() *
+ orientation());
+
+ errors_.emplace_back(
+ Eigen::Matrix<Scalar, 3, 1>(error.x(), error.y(), error.z()));
+ position_errors_.emplace_back(y);
+
+ ObserveCameraUpdate(t, rt.first, imu_to_world_rotation, imu_to_world);
+ }
+
+ virtual void ObserveIMUUpdate(
+ distributed_clock::time_point /*t*/,
+ std::pair<Eigen::Vector3d, Eigen::Vector3d> /*wa*/) {}
+
+ void UpdateIMU(distributed_clock::time_point t,
+ std::pair<Eigen::Vector3d, Eigen::Vector3d> wa) override {
+ Integrate(t);
+ omega_ = wa.first;
+ accel_ = wa.second;
+
+ ObserveIMUUpdate(t, wa);
+ }
+
+ const Eigen::Quaternion<Scalar> &orientation() const { return orientation_; }
+
+ size_t num_errors() const { return errors_.size(); }
+ Scalar errorx(size_t i) const { return errors_[i].x(); }
+ Scalar errory(size_t i) const { return errors_[i].y(); }
+ Scalar errorz(size_t i) const { return errors_[i].z(); }
+
+ size_t num_perrors() const { return position_errors_.size(); }
+ Scalar errorpx(size_t i) const { return position_errors_[i].x(); }
+ Scalar errorpy(size_t i) const { return position_errors_[i].y(); }
+ Scalar errorpz(size_t i) const { return position_errors_[i].z(); }
+
+ private:
+ Eigen::Matrix<Scalar, 46, 1> Pack(Eigen::Quaternion<Scalar> q,
+ Eigen::Matrix<Scalar, 6, 1> x_hat,
+ Eigen::Matrix<Scalar, 6, 6> p) {
+ Eigen::Matrix<Scalar, 46, 1> result = Eigen::Matrix<Scalar, 46, 1>::Zero();
+ result.template block<4, 1>(0, 0) = q.coeffs();
+ result.template block<6, 1>(4, 0) = x_hat;
+ result.template block<36, 1>(10, 0) =
+ Eigen::Map<Eigen::Matrix<Scalar, 36, 1>>(p.data(), p.size());
+
+ return result;
+ }
+
+ std::tuple<Eigen::Quaternion<Scalar>, Eigen::Matrix<Scalar, 6, 1>,
+ Eigen::Matrix<Scalar, 6, 6>>
+ UnPack(Eigen::Matrix<Scalar, 46, 1> input) {
+ Eigen::Quaternion<Scalar> q(input.template block<4, 1>(0, 0));
+ Eigen::Matrix<Scalar, 6, 1> x_hat(input.template block<6, 1>(4, 0));
+ Eigen::Matrix<Scalar, 6, 6> p =
+ Eigen::Map<Eigen::Matrix<Scalar, 6, 6>>(input.data() + 10, 6, 6);
+ return std::make_tuple(q, x_hat, p);
+ }
+
+ Eigen::Matrix<Scalar, 46, 1> Derivative(
+ const Eigen::Matrix<Scalar, 46, 1> &input) {
+ auto [q, x_hat, p] = UnPack(input);
+
+ Eigen::Quaternion<Scalar> omega_q;
+ omega_q.w() = Scalar(0.0);
+ omega_q.vec() = 0.5 * (omega_.cast<Scalar>() - imu_bias_);
+ Eigen::Matrix<Scalar, 4, 1> q_dot = (q * omega_q).coeffs();
+
+ Eigen::Matrix<double, 6, 6> A = Eigen::Matrix<double, 6, 6>::Zero();
+ A(0, 3) = 1.0;
+ A(1, 4) = 1.0;
+ A(2, 5) = 1.0;
+
+ Eigen::Matrix<Scalar, 6, 1> x_hat_dot = A * x_hat;
+ x_hat_dot.template block<3, 1>(3, 0) =
+ orientation() * (accel_.cast<Scalar>() - accelerometer_bias_) -
+ Eigen::Vector3d(0, 0, kGravity).cast<Scalar>() * gravity_scalar_;
+
+ // Initialize the position noise to 0. If the solver is going to back-solve
+ // for the most likely starting position, let's just say that the noise is
+ // small.
+ constexpr double kPositionNoise = 0.0;
+ constexpr double kAccelerometerNoise = 2.3e-6 * 9.8;
+ constexpr double kIMUdt = 5.0e-4;
+ Eigen::Matrix<double, 6, 6> Q_dot(
+ (::Eigen::DiagonalMatrix<double, 6>().diagonal()
+ << ::std::pow(kPositionNoise, 2) / kIMUdt,
+ ::std::pow(kPositionNoise, 2) / kIMUdt,
+ ::std::pow(kPositionNoise, 2) / kIMUdt,
+ ::std::pow(kAccelerometerNoise, 2) / kIMUdt,
+ ::std::pow(kAccelerometerNoise, 2) / kIMUdt,
+ ::std::pow(kAccelerometerNoise, 2) / kIMUdt)
+ .finished()
+ .asDiagonal());
+ Eigen::Matrix<Scalar, 6, 6> p_dot = A.cast<Scalar>() * p +
+ p * A.transpose().cast<Scalar>() +
+ Q_dot.cast<Scalar>();
+
+ return Pack(Eigen::Quaternion<Scalar>(q_dot), x_hat_dot, p_dot);
+ }
+
+ virtual void ObserveIntegrated(distributed_clock::time_point /*t*/,
+ Eigen::Matrix<Scalar, 6, 1> /*x_hat*/,
+ Eigen::Quaternion<Scalar> /*orientation*/,
+ Eigen::Matrix<Scalar, 6, 6> /*p*/) {}
+
+ void Integrate(distributed_clock::time_point t) {
+ if (last_time_ != distributed_clock::min_time) {
+ Eigen::Matrix<Scalar, 46, 1> next = control_loops::RungeKutta(
+ [this](auto r) { return Derivative(r); },
+ Pack(orientation_, x_hat_, p_),
+ aos::time::DurationInSeconds(t - last_time_));
+
+ std::tie(orientation_, x_hat_, p_) = UnPack(next);
+
+ // Normalize q so it doesn't drift.
+ orientation_.normalize();
+ }
+
+ last_time_ = t;
+ ObserveIntegrated(t, x_hat_, orientation_, p_);
+ }
+
+ Eigen::Matrix<double, 3, 1> accel_;
+ Eigen::Matrix<double, 3, 1> omega_;
+ Eigen::Matrix<Scalar, 3, 1> imu_bias_;
+
+ // IMU -> world quaternion
+ Eigen::Quaternion<Scalar> orientation_;
+ Eigen::Matrix<Scalar, 6, 1> x_hat_;
+ Eigen::Matrix<Scalar, 6, 6> p_;
+ distributed_clock::time_point last_time_ = distributed_clock::min_time;
+
+ Eigen::Quaternion<Scalar> imu_to_camera_rotation_;
+ Eigen::Translation<Scalar, 3> imu_to_camera_translation_ =
+ Eigen::Translation3d(0, 0, 0).cast<Scalar>();
+
+ Eigen::Quaternion<Scalar> board_to_world_;
+ Scalar gravity_scalar_;
+ Eigen::Matrix<Scalar, 3, 1> accelerometer_bias_;
+ // States:
+ // xyz position
+ // xyz velocity
+ //
+ // Inputs
+ // xyz accel
+ //
+ // Measurement:
+ // xyz position from camera.
+ //
+ // Since the gyro is so good, we can just solve for the bias and initial
+ // position with the solver and see what it learns.
+
+ // Returns the angular errors for each camera sample.
+ std::vector<Eigen::Matrix<Scalar, 3, 1>> errors_;
+ std::vector<Eigen::Matrix<Scalar, 3, 1>> position_errors_;
+};
+
+// Subclass of the filter above which has plotting. This keeps debug code and
+// actual code separate.
+class PoseFilter : public CeresPoseFilter<double> {
+ public:
+ PoseFilter(Eigen::Quaternion<double> initial_orientation,
+ Eigen::Quaternion<double> imu_to_camera,
+ Eigen::Matrix<double, 3, 1> gyro_bias,
+ Eigen::Matrix<double, 6, 1> initial_state,
+ Eigen::Quaternion<double> board_to_world,
+ Eigen::Matrix<double, 3, 1> imu_to_camera_translation,
+ double gravity_scalar,
+ Eigen::Matrix<double, 3, 1> accelerometer_bias)
+ : CeresPoseFilter<double>(initial_orientation, imu_to_camera, gyro_bias,
+ initial_state, board_to_world,
+ imu_to_camera_translation, gravity_scalar,
+ accelerometer_bias) {}
+
+ void Plot() {
+ std::vector<double> rx;
+ std::vector<double> ry;
+ std::vector<double> rz;
+ std::vector<double> x;
+ std::vector<double> y;
+ std::vector<double> z;
+ std::vector<double> vx;
+ std::vector<double> vy;
+ std::vector<double> vz;
+ for (const Eigen::Quaternion<double> &q : orientations_) {
+ Eigen::Matrix<double, 3, 1> rotation_vector =
+ frc971::controls::ToRotationVectorFromQuaternion(q);
+ rx.emplace_back(rotation_vector(0, 0));
+ ry.emplace_back(rotation_vector(1, 0));
+ rz.emplace_back(rotation_vector(2, 0));
+ }
+ for (const Eigen::Matrix<double, 6, 1> &x_hat : x_hats_) {
+ x.emplace_back(x_hat(0));
+ y.emplace_back(x_hat(1));
+ z.emplace_back(x_hat(2));
+ vx.emplace_back(x_hat(3));
+ vy.emplace_back(x_hat(4));
+ vz.emplace_back(x_hat(5));
+ }
+
+ frc971::analysis::Plotter plotter;
+ plotter.AddFigure("position");
+ plotter.AddLine(times_, rx, "x_hat(0)");
+ plotter.AddLine(times_, ry, "x_hat(1)");
+ plotter.AddLine(times_, rz, "x_hat(2)");
+ plotter.AddLine(ct, cx, "Camera x");
+ plotter.AddLine(ct, cy, "Camera y");
+ plotter.AddLine(ct, cz, "Camera z");
+ plotter.AddLine(ct, cerrx, "Camera error x");
+ plotter.AddLine(ct, cerry, "Camera error y");
+ plotter.AddLine(ct, cerrz, "Camera error z");
+ plotter.Publish();
+
+ plotter.AddFigure("error");
+ plotter.AddLine(times_, rx, "x_hat(0)");
+ plotter.AddLine(times_, ry, "x_hat(1)");
+ plotter.AddLine(times_, rz, "x_hat(2)");
+ plotter.AddLine(ct, cerrx, "Camera error x");
+ plotter.AddLine(ct, cerry, "Camera error y");
+ plotter.AddLine(ct, cerrz, "Camera error z");
+ plotter.Publish();
+
+ plotter.AddFigure("imu");
+ plotter.AddLine(ct, world_gravity_x, "world_gravity(0)");
+ plotter.AddLine(ct, world_gravity_y, "world_gravity(1)");
+ plotter.AddLine(ct, world_gravity_z, "world_gravity(2)");
+ plotter.AddLine(imut, imu_x, "imu x");
+ plotter.AddLine(imut, imu_y, "imu y");
+ plotter.AddLine(imut, imu_z, "imu z");
+ plotter.AddLine(times_, rx, "rotation x");
+ plotter.AddLine(times_, ry, "rotation y");
+ plotter.AddLine(times_, rz, "rotation z");
+ plotter.Publish();
+
+ plotter.AddFigure("raw");
+ plotter.AddLine(imut, imu_x, "imu x");
+ plotter.AddLine(imut, imu_y, "imu y");
+ plotter.AddLine(imut, imu_z, "imu z");
+ plotter.AddLine(imut, imu_ratex, "omega x");
+ plotter.AddLine(imut, imu_ratey, "omega y");
+ plotter.AddLine(imut, imu_ratez, "omega z");
+ plotter.AddLine(ct, raw_cx, "Camera x");
+ plotter.AddLine(ct, raw_cy, "Camera y");
+ plotter.AddLine(ct, raw_cz, "Camera z");
+ plotter.Publish();
+
+ plotter.AddFigure("xyz vel");
+ plotter.AddLine(times_, x, "x");
+ plotter.AddLine(times_, y, "y");
+ plotter.AddLine(times_, z, "z");
+ plotter.AddLine(times_, vx, "vx");
+ plotter.AddLine(times_, vy, "vy");
+ plotter.AddLine(times_, vz, "vz");
+ plotter.AddLine(ct, camera_position_x, "Camera x");
+ plotter.AddLine(ct, camera_position_y, "Camera y");
+ plotter.AddLine(ct, camera_position_z, "Camera z");
+ plotter.Publish();
+
+ plotter.Spin();
+ }
+
+ void ObserveIntegrated(distributed_clock::time_point t,
+ Eigen::Matrix<double, 6, 1> x_hat,
+ Eigen::Quaternion<double> orientation,
+ Eigen::Matrix<double, 6, 6> p) override {
+ VLOG(1) << t << " -> " << p;
+ VLOG(1) << t << " xhat -> " << x_hat.transpose();
+ times_.emplace_back(chrono::duration<double>(t.time_since_epoch()).count());
+ x_hats_.emplace_back(x_hat);
+ orientations_.emplace_back(orientation);
+ }
+
+ void ObserveIMUUpdate(
+ distributed_clock::time_point t,
+ std::pair<Eigen::Vector3d, Eigen::Vector3d> wa) override {
+ imut.emplace_back(chrono::duration<double>(t.time_since_epoch()).count());
+ imu_ratex.emplace_back(wa.first.x());
+ imu_ratey.emplace_back(wa.first.y());
+ imu_ratez.emplace_back(wa.first.z());
+ imu_x.emplace_back(wa.second.x());
+ imu_y.emplace_back(wa.second.y());
+ imu_z.emplace_back(wa.second.z());
+
+ last_accel_ = wa.second;
+ }
+
+ void ObserveCameraUpdate(distributed_clock::time_point t,
+ Eigen::Vector3d board_to_camera_rotation,
+ Eigen::Quaternion<double> imu_to_world_rotation,
+ Eigen::Affine3d imu_to_world) override {
+ raw_cx.emplace_back(board_to_camera_rotation(0, 0));
+ raw_cy.emplace_back(board_to_camera_rotation(1, 0));
+ raw_cz.emplace_back(board_to_camera_rotation(2, 0));
+
+ Eigen::Matrix<double, 3, 1> rotation_vector =
+ frc971::controls::ToRotationVectorFromQuaternion(imu_to_world_rotation);
+ ct.emplace_back(chrono::duration<double>(t.time_since_epoch()).count());
+
+ Eigen::Matrix<double, 3, 1> cerr =
+ frc971::controls::ToRotationVectorFromQuaternion(
+ imu_to_world_rotation.inverse() * orientation());
+
+ cx.emplace_back(rotation_vector(0, 0));
+ cy.emplace_back(rotation_vector(1, 0));
+ cz.emplace_back(rotation_vector(2, 0));
+
+ cerrx.emplace_back(cerr(0, 0));
+ cerry.emplace_back(cerr(1, 0));
+ cerrz.emplace_back(cerr(2, 0));
+
+ const Eigen::Vector3d world_gravity =
+ imu_to_world_rotation * last_accel_ -
+ Eigen::Vector3d(0, 0, kGravity) * gravity_scalar();
+
+ const Eigen::Vector3d camera_position =
+ imu_to_world * Eigen::Vector3d::Zero();
+
+ world_gravity_x.emplace_back(world_gravity.x());
+ world_gravity_y.emplace_back(world_gravity.y());
+ world_gravity_z.emplace_back(world_gravity.z());
+
+ camera_position_x.emplace_back(camera_position.x());
+ camera_position_y.emplace_back(camera_position.y());
+ camera_position_z.emplace_back(camera_position.z());
+ }
+
+ std::vector<double> ct;
+ std::vector<double> cx;
+ std::vector<double> cy;
+ std::vector<double> cz;
+ std::vector<double> raw_cx;
+ std::vector<double> raw_cy;
+ std::vector<double> raw_cz;
+ std::vector<double> cerrx;
+ std::vector<double> cerry;
+ std::vector<double> cerrz;
+
+ std::vector<double> world_gravity_x;
+ std::vector<double> world_gravity_y;
+ std::vector<double> world_gravity_z;
+ std::vector<double> imu_x;
+ std::vector<double> imu_y;
+ std::vector<double> imu_z;
+ std::vector<double> camera_position_x;
+ std::vector<double> camera_position_y;
+ std::vector<double> camera_position_z;
+
+ std::vector<double> imut;
+ std::vector<double> imu_ratex;
+ std::vector<double> imu_ratey;
+ std::vector<double> imu_ratez;
+
+ std::vector<double> times_;
+ std::vector<Eigen::Matrix<double, 6, 1>> x_hats_;
+ std::vector<Eigen::Quaternion<double>> orientations_;
+
+ Eigen::Matrix<double, 3, 1> last_accel_ = Eigen::Matrix<double, 3, 1>::Zero();
+};
+
+// Adapter class from the KF above to a Ceres cost function.
+struct CostFunctor {
+ CostFunctor(const CalibrationData *d) : data(d) {}
+
+ const CalibrationData *data;
+
+ template <typename S>
+ bool operator()(const S *const q1, const S *const q2, const S *const v,
+ const S *const p, const S *const btw, const S *const itc,
+ const S *const gravity_scalar_ptr,
+ const S *const accelerometer_bias_ptr, S *residual) const {
+ Eigen::Quaternion<S> initial_orientation(q1[3], q1[0], q1[1], q1[2]);
+ Eigen::Quaternion<S> mounting_orientation(q2[3], q2[0], q2[1], q2[2]);
+ Eigen::Quaternion<S> board_to_world(btw[3], btw[0], btw[1], btw[2]);
+ Eigen::Matrix<S, 3, 1> gyro_bias(v[0], v[1], v[2]);
+ Eigen::Matrix<S, 6, 1> initial_state;
+ initial_state(0) = p[0];
+ initial_state(1) = p[1];
+ initial_state(2) = p[2];
+ initial_state(3) = p[3];
+ initial_state(4) = p[4];
+ initial_state(5) = p[5];
+ Eigen::Matrix<S, 3, 1> imu_to_camera_translation(itc[0], itc[1], itc[2]);
+ Eigen::Matrix<S, 3, 1> accelerometer_bias(accelerometer_bias_ptr[0],
+ accelerometer_bias_ptr[1],
+ accelerometer_bias_ptr[2]);
+
+ CeresPoseFilter<S> filter(initial_orientation, mounting_orientation,
+ gyro_bias, initial_state, board_to_world,
+ imu_to_camera_translation, *gravity_scalar_ptr,
+ accelerometer_bias);
+ data->ReviewData(&filter);
+
+ for (size_t i = 0; i < filter.num_errors(); ++i) {
+ residual[3 * i + 0] = filter.errorx(i);
+ residual[3 * i + 1] = filter.errory(i);
+ residual[3 * i + 2] = filter.errorz(i);
+ }
+
+ for (size_t i = 0; i < filter.num_perrors(); ++i) {
+ residual[3 * filter.num_errors() + 3 * i + 0] = filter.errorpx(i);
+ residual[3 * filter.num_errors() + 3 * i + 1] = filter.errorpy(i);
+ residual[3 * filter.num_errors() + 3 * i + 2] = filter.errorpz(i);
+ }
+
+ return true;
+ }
+};
+
+void Solve(const CalibrationData &data,
+ CalibrationParameters *calibration_parameters) {
+ ceres::Problem problem;
+
+ ceres::EigenQuaternionParameterization *quaternion_local_parameterization =
+ new ceres::EigenQuaternionParameterization();
+ // Set up the only cost function (also known as residual). This uses
+ // auto-differentiation to obtain the derivative (jacobian).
+
+ ceres::CostFunction *cost_function =
+ new ceres::AutoDiffCostFunction<CostFunctor, ceres::DYNAMIC, 4, 4, 3, 6,
+ 4, 3, 1, 3>(
+ new CostFunctor(&data), data.camera_samples_size() * 6);
+ problem.AddResidualBlock(
+ cost_function, new ceres::HuberLoss(1.0),
+ calibration_parameters->initial_orientation.coeffs().data(),
+ calibration_parameters->imu_to_camera.coeffs().data(),
+ calibration_parameters->gyro_bias.data(),
+ calibration_parameters->initial_state.data(),
+ calibration_parameters->board_to_world.coeffs().data(),
+ calibration_parameters->imu_to_camera_translation.data(),
+ &calibration_parameters->gravity_scalar,
+ calibration_parameters->accelerometer_bias.data());
+ problem.SetParameterization(
+ calibration_parameters->initial_orientation.coeffs().data(),
+ quaternion_local_parameterization);
+ problem.SetParameterization(
+ calibration_parameters->imu_to_camera.coeffs().data(),
+ quaternion_local_parameterization);
+ problem.SetParameterization(
+ calibration_parameters->board_to_world.coeffs().data(),
+ quaternion_local_parameterization);
+ for (int i = 0; i < 3; ++i) {
+ problem.SetParameterLowerBound(calibration_parameters->gyro_bias.data(), i,
+ -0.05);
+ problem.SetParameterUpperBound(calibration_parameters->gyro_bias.data(), i,
+ 0.05);
+ problem.SetParameterLowerBound(
+ calibration_parameters->accelerometer_bias.data(), i, -0.05);
+ problem.SetParameterUpperBound(
+ calibration_parameters->accelerometer_bias.data(), i, 0.05);
+ }
+ problem.SetParameterLowerBound(&calibration_parameters->gravity_scalar, 0,
+ 0.95);
+ problem.SetParameterUpperBound(&calibration_parameters->gravity_scalar, 0,
+ 1.05);
+
+ // Run the solver!
+ ceres::Solver::Options options;
+ options.minimizer_progress_to_stdout = true;
+ options.gradient_tolerance = 1e-12;
+ options.function_tolerance = 1e-16;
+ options.parameter_tolerance = 1e-12;
+ ceres::Solver::Summary summary;
+ Solve(options, &problem, &summary);
+ LOG(INFO) << summary.FullReport();
+
+ LOG(INFO) << "initial_orientation "
+ << calibration_parameters->initial_orientation.coeffs().transpose();
+ LOG(INFO) << "imu_to_camera "
+ << calibration_parameters->imu_to_camera.coeffs().transpose();
+ LOG(INFO) << "imu_to_camera(rotation) "
+ << frc971::controls::ToRotationVectorFromQuaternion(
+ calibration_parameters->imu_to_camera)
+ .transpose();
+ LOG(INFO) << "gyro_bias " << calibration_parameters->gyro_bias.transpose();
+ LOG(INFO) << "board_to_world "
+ << calibration_parameters->board_to_world.coeffs().transpose();
+ LOG(INFO) << "board_to_world(rotation) "
+ << frc971::controls::ToRotationVectorFromQuaternion(
+ calibration_parameters->board_to_world)
+ .transpose();
+ LOG(INFO) << "imu_to_camera_translation "
+ << calibration_parameters->imu_to_camera_translation.transpose();
+ LOG(INFO) << "gravity " << kGravity * calibration_parameters->gravity_scalar;
+ LOG(INFO) << "accelerometer bias "
+ << calibration_parameters->accelerometer_bias.transpose();
+}
+
+void Plot(const CalibrationData &data,
+ const CalibrationParameters &calibration_parameters) {
+ PoseFilter filter(calibration_parameters.initial_orientation,
+ calibration_parameters.imu_to_camera,
+ calibration_parameters.gyro_bias,
+ calibration_parameters.initial_state,
+ calibration_parameters.board_to_world,
+ calibration_parameters.imu_to_camera_translation,
+ calibration_parameters.gravity_scalar,
+ calibration_parameters.accelerometer_bias);
+ data.ReviewData(&filter);
+ filter.Plot();
+}
+
+} // namespace vision
+} // namespace frc971
diff --git a/frc971/vision/extrinsics_calibration.h b/frc971/vision/extrinsics_calibration.h
new file mode 100644
index 0000000..9d6c704
--- /dev/null
+++ b/frc971/vision/extrinsics_calibration.h
@@ -0,0 +1,39 @@
+#ifndef FRC971_VISION_EXTRINSICS_CALIBRATION_H_
+#define FRC971_VISION_EXTRINSICS_CALIBRATION_H_
+
+#include "Eigen/Dense"
+#include "Eigen/Geometry"
+#include "frc971/vision/calibration_accumulator.h"
+
+namespace frc971 {
+namespace vision {
+
+struct CalibrationParameters {
+ Eigen::Quaternion<double> initial_orientation =
+ Eigen::Quaternion<double>::Identity();
+ Eigen::Quaternion<double> imu_to_camera =
+ Eigen::Quaternion<double>::Identity();
+ Eigen::Quaternion<double> board_to_world =
+ Eigen::Quaternion<double>::Identity();
+
+ Eigen::Vector3d gyro_bias = Eigen::Vector3d::Zero();
+ Eigen::Matrix<double, 6, 1> initial_state =
+ Eigen::Matrix<double, 6, 1>::Zero();
+ Eigen::Matrix<double, 3, 1> imu_to_camera_translation =
+ Eigen::Matrix<double, 3, 1>::Zero();
+
+ double gravity_scalar = 1.0;
+ Eigen::Matrix<double, 3, 1> accelerometer_bias =
+ Eigen::Matrix<double, 3, 1>::Zero();
+};
+
+void Solve(const CalibrationData &data,
+ CalibrationParameters *calibration_parameters);
+
+void Plot(const CalibrationData &data,
+ const CalibrationParameters &calibration_parameters);
+
+} // namespace vision
+} // namespace frc971
+
+#endif // FRC971_VISION_EXTRINSICS_CALIBRATION_H_